Structural phase transition and high-pressure elastic behavior of III-V semiconductors

Abstract

We have expressed the Gibbs free energy for III-V compound semiconductors as a function of pressure and charge transfer through three-body interactions. The lattice energy in it has been represented by a three-body potential consisting of the long-range Coulomb and three-body interactions, and the short-range van der Waals attraction and overlap repulsion, effective up to the second-neighbor ions. We have depicted the phase diagrams and found that the abrupt volume collapses at the phase-transition pressures agree fairly well with the observed data. The phasetransition pressures (17.0, 4.0, 17.1, 18.0, 1.0, and 11. 0 GPa) obtained by us are in close agreement with the experimental data (18.5, 6.7, 22.0, 8.4, 2.2, and 10.8 GPa) for almost all the semiconductors (GaAs, GaSb, GaP, InAs, InSb, and InP) under consideration. The elastic stiffness constants (C») have been found to increase with pressure while the shear moduli (C» -C&z)/2 and C44 decrease with it, and this feature is consistent with the experimental observations.

Structural properties of silver iodide and copper iodide

“…[19,20] and reported in Table 1. We have computed the structural phase transition pressure (P ) following the minimization technique of Gibbs free energies [29,32] Table 2 and compared with the available experimental data [33][34][35]. Our results on cohesive energy are in good agreement with the available experimental data in the respective phases.…”

“…Eq. (5) is the van der Waals (vdW) interaction, due to the dipole-dipole (dd) and dipole-quadrupole (d-q) interactions with C (X )and D(X )as their overall coefficients [29], obtained using the Slater Kirwood Variation (SKV) method. The last equation is the Hafemeister-Flygare (HF) type [30] repulsive interaction operative up to the second neighbour ions.…”

TBI Calculations of the Elastic Properties and Structural Phase Transformation in Novel Materials: Yttrium Nitride

“…These effects have been incorporated in the Gibbs free energy G as a function of pressure (P ) and three-body interactions (TBI) [17], which are the most dominant among many-body contributions. Three-body interactions are of great importance at high pressure when the interionic separation decreases considerably and coordination number increases.…”

“…The lattice energies given by Eqs. (3) and (4) contain only three model parameters (b, ρ and f (r)) whose values have been determined from measured interionic separation and cohesive energy after choosing an appropriate value of ρ [17]. To understand elastic properties of these transition metal compounds we have calculated second order elastic constants (SOEC), C 11 C 12 and C 44 , and their pressure derivatives at 0 K, since these elastic constants are functions of first and second order derivatives of short range potential, so their calculation will provide knowledge about the effect of short range forces on these materials following Sharma et al [18] and Singh et al [19] and Shanker et al [20,21].…”

“…The three-body interactions have been considered to arise from the charge transfer effects during the overlapping of electron shells of the adjacent ions [16]. This three-body potential model (TBPM) has been found to be successful in describing the phase transition, phonon dispersion, harmonic and anharmonic properties of ionic and semiconductor solids [16][17][18][19][20][21][22][23][24].…”